Comments
The first thing to learn is really how to write non-code text (Crazy right?). Comments won't be interpreted, so they are a great way to document your code.
- Single line comments:
// text
//This is a comment
- Multiline comments:
/* text */
/*
this is
also a
comment
*/
Variables
Keywords
There are 3 main ways to declare a variable: var
, let
and const
. The difference is that:
-
var
is used in pre-ES6 version of JavaScript -
let
declares a variable that the content can change. -
const
declares a variable that the content can't and shouldn't change.
var name = 'Vitor 💁♂️️'
let country = 'Brazil 🇧🇷️'
const hobby = 'Music 🎵️'
console.log
If you want to see these variables in the console, use console.log
.
console.log(name, country, hobby)
//Prints: Vitor 💁♂️️ Brazil 🇧🇷️ Music 🎵️
Reassign
When reassigning you don't need the keywords. But if you try to reassign const
variables, it will throw an error.
country = 'Japan 🇯🇵️' //Ok
hobby = 'Eating 🥨️' //error: TypeError: invalid assignment to const 'hobby'
Types of Data
Strings
They can be indicated by single or double quotes.
const stringIsText = 'I like dancing 💃️'
const thisIsAlsoString = "I also like cooking 🍳️"
Numbers
const myFavoriteNumber = 12
Float
const myBudget = 25.2
Boolean
const loveMusic = true
Array
const myFavoriteMeals = ['Shrimp 🍤️','Cake 🎂️','Potato 🥔️']
Objects
const seriesRating = {
title: ['Dark ⏰️', 'La Casa de Papel 🏦️', 'The Umbrella Academy ☂️'],
score: [10, 9 ,8]
}
Mathematical Operations
Symbols
// ➕️ addition
5 + 5
// ➖️ subtraction
5 - 2
// ✖️ multiplication
5 * 5
// ➗️ division
5 + 2
// ❔️ modulo
5 % 2
Assignment Operators
These operators are used to perform an operation and assign at the same time. To save some typing, instead of writing x = x + 2
you can write x+= 2
.
+=
addition assignment
-=
subtraction assignment
*=
multiplication assignment
/=
division assignment
let moneyEarned = 20
moneyEarned *= 3 //Same as: timePraticed = timePraticed * 3
console.log(timePraticed) //Prints: 60
I really appreciate if you share what you thought and maybe something you struggle so I can cover in the following posts 🤗️
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